math question math

Question

What is the equation of the line that passes through the point (−1,4) and has a slope of −5 



Answer 1

slope = m = -5

(y-4)/(x+1) = -5

y-4 = -5x -5

y = -5x-5+4 = -5x -1

y = -5x -1

or

5x+y +1 = 0

the general linear equation is y=mx + b

where m=the slope = -5

y=-5x+b plug in the point (-1, 4) to solve for b

4 =-5(-1) + b

b = 4-5=9-1

y =-5x -1

5x +y +1 = 0

Answer 2

Hi Porter.

This is a linear equation question. We know all linear equations can be written in the form y=mx+b, where m is the slope, b is the y intercept and x and y are values for the equation at a specific point. As long as you know 3 pieces of information you can solve

Let plug in what we know so far

y=mx+b, x= -1 y=4 and m-5 based on what we are given.

4=-5(-1)+b

remember here a negative times a negative is a positive, so we have

4= 5+b

now subtract 5 to get b alone and we find b=-1

Now plug back in, remember x and y stay as variables, we can plug in any value later on.

So our final equation is y=-5x-1, using a slope of -5 as given and the -1 intercept we found.